代码创建的PieChartView无法显示，求问题排查解决方法

我尝试通过代码方式显示PieChartView，但无法成功实现。以下是我的代码：

// Create pie chart view
let pieChart: PieChartView = {
    let pieChart = PieChartView()
    pieChart.translatesAutoresizingMaskIntoConstraints = false
    pieChart.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    return pieChart
}()

setPieChartData(chartView: pieChart, labels: labels, values: values)
        
setupViews() // Here I am adding the piechart view as follows
view.addSubview(pieChart)

NSLayoutConstraint.activate([
    pieChart.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 180),
    pieChart.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20)])
        
pieChart.setNeedsDisplay()


func setPieChartData(chartView: PieChartView, labels: [String], values: [Double]) {
    var entries: [PieChartDataEntry] = []
    for i in 0..<labels.count {
        entries.append(PieChartDataEntry(value: values[i], label: labels[i]))
    }
    let dataSet = PieChartDataSet(entries: entries, label: "Pie Chart")
    dataSet.colors = [.orange, .red]
//    dataSet.drawValuesEnabled = true // Hide values on chart
//    
//    // Set additional properties for donut chart
//    dataSet.drawIconsEnabled = true
//    dataSet.drawValuesEnabled = true
//    dataSet.sliceSpace = 2.0 // Adjust space between slices to create donut effect
            
    let data = PieChartData(dataSet: dataSet)
    chartView.data = data
}

请问我遗漏了什么配置？我尝试添加背景色、修改约束，但问题仍未解决。

可能遗漏的配置点 #

• 约束不完整且存在冲突
  你只给PieChartView设置了top和leading约束，没有定义宽度和高度，视图没有明确尺寸自然无法显示。同时，translatesAutoresizingMaskIntoConstraints = false和autoresizingMask规则冲突——前者启用AutoLayout，后者是旧的自动调整逻辑，必须删掉autoresizingMask这一行。
  补充完整约束的示例：

  NSLayoutConstraint.activate([
      pieChart.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 180),
      pieChart.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
      pieChart.widthAnchor.constraint(equalToConstant: 300),
      pieChart.heightAnchor.constraint(equalToConstant: 300)
  ])
  

• 数据设置时机错误
  你在调用setupViews（添加子视图）之前就执行了setPieChartData，此时PieChartView还未被加入视图层级，数据绑定可能失效。应该把setPieChartData放在view.addSubview(pieChart)和约束设置完成之后。

• 缺少基础渲染配置
  可以添加一些基础配置确保图表正常渲染，同时方便排查数据是否加载：

  let pieChart: PieChartView = {
      let pieChart = PieChartView()
      pieChart.translatesAutoresizingMaskIntoConstraints = false
      pieChart.chartDescription.enabled = false // 关闭默认底部描述
      pieChart.legend.enabled = true // 显示图例，确认数据是否存在
      pieChart.holeRadiusPercent = 0.0 // 0为纯饼图，大于0则是环形图
      return pieChart
  }()
  

• 数据有效性未验证
  PieChart不支持非正数的数值，且labels和values数组长度必须一致。在setPieChartData中添加校验：

  func setPieChartData(chartView: PieChartView, labels: [String], values: [Double]) {
      guard labels.count == values.count else { return }
      guard values.allSatisfy({ $0 > 0 }) else { return }
      
      var entries: [PieChartDataEntry] = []
      for i in 0..<labels.count {
          entries.append(PieChartDataEntry(value: values[i], label: labels[i]))
      }
      // 后续代码不变
  }
  

内容的提问来源于stack exchange，提问作者Gaurav Patil